Gentlemen,

Please help with throttle surging (glitching?)

So, I started working on the CP+ after two weeks away. I removed the MH A/R gear and reinstalled the stock main gear/shaft (that upgrade seemed noisy and also seemed to reduce flight times). She's now back to the nice quiet sound from before. Test hovering in the garage I noticed some quick forward pitching. No glitch in any other direction. I did some searching here and concluded I should replace both motors as they had enough hours on them anyway (had recently replaced all 3 original S-75s). That seemed to do the trick on the forward pitching.

Then, off to the Basketball gym (too windy outside today) to fly in a larger space. I've been noticing lately that I couldn't ever get the tail to stop seeking or twitching. Regardless of what combination of proportional and gyro settings I tried. When it was new it was very nice in this regard though so that's been an unwelcome change. Well, while making many test hops tweaking the tail, the throttle started surging terribly. I mean real aggressive, like you took the stick and jammed it for just a second then back to where it was. Of course, when this happens the tail doesn't hold so I'm fighting yaw too. This was real scary and unpredictable. It did it on several different batteries so I just decided to quit and come home to post here for help.

I put 3 new s-75s on when I replaced the main frame several weeks ago and also put on a new swash. So it has lots of new, but still stock, parts. Hope someone has an idea what to try next. It has really deteriorated and now I'm scared to fly it in the current condition.

Thanks,

Scott